U.S. patent number 8,930,061 [Application Number 12/666,522] was granted by the patent office on 2015-01-06 for method and apparatus for influencing the transverse dynamics of a vehicle.
This patent grant is currently assigned to Daimler AG. The grantee listed for this patent is Dieter Ammon, Jens Kalkkuhl, Daniel Keppler, Magnus Rau, Avshalom Suissa. Invention is credited to Dieter Ammon, Jens Kalkkuhl, Daniel Keppler, Magnus Rau, Avshalom Suissa.
United States Patent |
8,930,061 |
Ammon , et al. |
January 6, 2015 |
Method and apparatus for influencing the transverse dynamics of a
vehicle
Abstract
In a method and apparatus for influencing transverse dynamics of
a vehicle, for a chassis intervention is carried out when an
intervention condition is met. The intervention condition is met
when the value of a determined transverse dynamics disturbance
variable is higher than a disturbance variable threshold value, and
when one or a group of the following criteria is met: the
longitudinal speed of the vehicle is higher than a longitudinal
speed threshold value of the vehicle; the sensorially detected
actual yaw rate is lower than or equal to a calculated current yaw
rate; a braking torque variable describing a braking torque and
caused by braking by the driver is lower than or equal to a braking
torque threshold value; a spring variable describing the current
spring path of a chassis spring of a vehicle wheel is lower than or
equal to a spring path threshold value; a differential spring
variable describing the difference between the current spring paths
of the two chassis springs of a vehicle axle is lower than or equal
to a differential spring path threshold value; and a slip
difference variable describing the slip difference between two
vehicle wheels is lower than or equal to a slip differential
threshold value.
Inventors: |
Ammon; Dieter (Remseck,
DE), Kalkkuhl; Jens (Holzgerlingen, DE),
Keppler; Daniel (Althengstett, DE), Rau; Magnus
(Kirchheim unter Teck, DE), Suissa; Avshalom
(Althengstett, DE) |
Applicant: |
Name |
City |
State |
Country |
Type |
Ammon; Dieter
Kalkkuhl; Jens
Keppler; Daniel
Rau; Magnus
Suissa; Avshalom |
Remseck
Holzgerlingen
Althengstett
Kirchheim unter Teck
Althengstett |
N/A
N/A
N/A
N/A
N/A |
DE
DE
DE
DE
DE |
|
|
Assignee: |
Daimler AG (Stuttgart,
DE)
|
Family
ID: |
40040133 |
Appl.
No.: |
12/666,522 |
Filed: |
June 4, 2008 |
PCT
Filed: |
June 04, 2008 |
PCT No.: |
PCT/EP2008/004458 |
371(c)(1),(2),(4) Date: |
June 04, 2010 |
PCT
Pub. No.: |
WO2009/000388 |
PCT
Pub. Date: |
December 31, 2008 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20100262328 A1 |
Oct 14, 2010 |
|
Foreign Application Priority Data
|
|
|
|
|
Jun 27, 2007 [DE] |
|
|
10 2007 029 605 |
|
Current U.S.
Class: |
701/29.2;
701/41 |
Current CPC
Class: |
B60T
8/17551 (20130101); B60T 8/17555 (20130101) |
Current International
Class: |
G06F
17/00 (20060101); B60T 8/1755 (20060101); B60T
8/00 (20060101); B62D 6/04 (20060101) |
Field of
Search: |
;701/29 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
40 14 365 |
|
Nov 1990 |
|
DE |
|
44 19 650 |
|
Jul 1995 |
|
DE |
|
100 31 266 |
|
Jan 2001 |
|
DE |
|
100 53 604 |
|
May 2002 |
|
DE |
|
102 36 331 |
|
Feb 2004 |
|
DE |
|
10 2004 017 638 |
|
Oct 2005 |
|
DE |
|
10 2004 047 860 |
|
Apr 2006 |
|
DE |
|
0 529 258 |
|
Mar 1993 |
|
EP |
|
1 000 838 |
|
May 2000 |
|
EP |
|
3-125614 |
|
May 1991 |
|
JP |
|
2002-211380 |
|
Jul 2002 |
|
JP |
|
WO 99/26811 |
|
Jun 1999 |
|
WO |
|
WO 99/58381 |
|
Nov 1999 |
|
WO |
|
WO 2006/037678 |
|
Apr 2006 |
|
WO |
|
Other References
Form PCT/ISA/220 (one (1) page). cited by applicant .
Form PCT/ISA/237 (six (6) pages). cited by applicant .
International Search Report dated Dec. 29, 2008 w/partial English
translation (six (6) pages). cited by applicant .
Japanese Office Action dated Nov. 9, 2011 (Three (3) pages). cited
by applicant .
Van Zanten, Anton T. et al., "950759 VDC, The Vehicle Dynamics
Control System of Bosch," Robert Bosch GmbH, pp. 9-26. cited by
applicant .
Von Anton van Zanten, et al., "FDR-Die Fahrdynamik-regelung von
Bosch," ATZ Automobiltechische Zeitschrift 96 (1994); pp. 674-689.
cited by applicant .
Opposition document in European Patent Application No. 08759014.7
dated Nov. 22, 2011. cited by applicant .
Japanese-language Office Action dated Mar. 26, 2013 w/ partial
English translation (four (4) pages). cited by applicant .
German-language Summons to Oral Proceeding under Rule 115 dated
Apr. 11, 2014 (7 pages). cited by applicant.
|
Primary Examiner: Nguyen; Hiep V
Attorney, Agent or Firm: Crowell & Moring LLP
Claims
The invention claimed is:
1. A method for influencing the transverse dynamics of a vehicle,
said method comprising: detecting, by a disturbance variable
determination device, a transverse dynamics disturbance variable
acting on the vehicle; checking, by a checking device, whether a
preset intervention condition is fulfilled; and if an intervention
condition is fulfilled, carrying out a chassis intervention to
influence the transverse vehicle dynamics; wherein the intervention
condition is fulfilled when the magnitude of the determined
transverse dynamics disturbance variable is higher than a
disturbance variable threshold value, and when at least two of the
following criteria are fulfilled longitudinal speed of the vehicle
is higher than a longitudinal speed threshold value of the vehicle;
a sensor detected actual yaw rate is lower than a calculated
current yaw rate; and a slip difference variable describing the
slip difference between two vehicle wheels is lower than or equal
to a slip differential threshold value.
2. The method according to claim 1, wherein detecting said
transverse dynamics disturbance comprises detecting said transverse
dynamics disturbance on a chassis of the vehicle.
3. The method according to claim 2, wherein: a lateral wind acting
on the chassis of the vehicle by means of the disturbance variable
determination device is recognized; and a corresponding disturbance
of the transverse dynamics of the vehicle is compensated at least
partially.
4. The method according to claim 1, wherein the intervention
condition is fulfilled if at least one of the following is true:
the amount of the steering wheel angle is lower than or equal to a
steering angle threshold value; and the amount of the steering
wheel angle speed is lower than or equal to a steering angle speed
threshold value.
5. The method according to claim 1, wherein the intervention
condition is fulfilled when stationary transverse acceleration of
the vehicle is smaller than or equal to a transverse acceleration
threshold value.
6. The method according to claim 1, wherein an intervention
determination value is determined, which describes at least one of:
the amount of the transverse dynamic disturbance variable; the
amount of the yaw rate to be adjusted by means of the transverse
dynamics disturbance variable for compensating the transverse
disturbance; and the amount of another variable correlating with
one of the two variables.
7. The method according to claim 6, wherein said chassis
intervention comprises at least one of, a braking intervention at
at least one vehicle wheel; an influence of the wheel loads at at
least one vehicle wheel; an influencing of the servo torque of a
servo motor of a servo steering system; and a change of at least
one wheel drive torque at at least one vehicle wheel; and when a
magnitude of the intervention determination value is below a lower
threshold value, only one of the wheels, especially one of the
non-steerable wheels is braked via the respective associated
braking device.
8. The method according to claim 6, wherein: said chassis
intervention comprises at least one of: a braking intervention at
at least one vehicle wheel; an influence of the wheel loads at at
least one vehicle wheel; an influencing of the servo torque of a
servo motor of a servo steering system; and a change of at least
one wheel drive torque at at least one vehicle wheel; the
intervention determination value is greater than or equal to the
lower threshold value, and lower than an upper threshold value,
only one of the steerable wheels is braked at the front axle via
the respective associated braking device.
9. The method according to claim 6, wherein: said chassis
intervention comprises at least one of: a braking intervention at
at least one vehicle wheel; an influence of the wheel loads at at
least one vehicle wheel; an influencing of the servo torque of a
servo motor of a servo steering system; and a change of at least
one wheel drive torque at at least one vehicle wheel; if the
intervention determination value is greater than or equal to the
upper threshold value, both wheels of the same vehicle side are
braked via the respective associated braking device.
10. The method according to claim 6, wherein said chassis
intervention comprises at least one of, a braking intervention at
at least one vehicle wheel; an influence of the wheel loads at at
least one vehicle wheel; an influencing of the servo torque of a
servo motor of a servo steering system; and a change of at least
one wheel drive torque at at least one vehicle wheel; both wheels
of the same vehicle side are braked via associated braking devices;
and braking force distribution between a steerable wheel and a
corresponding non-steerable wheel of the same vehicle side is
parameter-dependent, and is preset in dependence on the vehicle
and/or can be adjusted according to the drive situation.
11. The method according to claim 1, wherein said chassis
intervention comprises at least one of: a braking intervention at
at least one vehicle wheel; an influence of the wheel loads at at
least one vehicle wheel; an influencing of the servo torque of a
servo motor of a servo steering system; and a change of at least
one wheel drive torque at at least one vehicle wheel.
12. The method according to claim 1, wherein a chassis intervention
which is triggered after fulfillment of the intervention condition
is ended, if at least one of the following is true: a braking
torque variable describing the the braking torque caused by the
driver is higher than a braking torque threshold value; the
magnitude of a vehicle steering angle is greater than a steering
angle threshold value; and the magnitude of steering angle speed is
greater than a steering angle speed threshold value.
13. The method according to claim 1, wherein the transverse
dynamics disturbance value is filtered by a high pass filter prior
to checking the intervention condition.
14. Apparatus for influencing transverse dynamics of a vehicle,
said apparatus comprising: a disturbance variable determination
device for determining the transverse dynamics disturbance variable
acting on the vehicle; a checking device which determines whether a
preset intervention condition is fulfilled; and a device which
implements a chassis intervention to influence the transverse
dynamics when the intervention condition is fulfilled; wherein, the
intervention condition is determined to be fulfilled when a
magnitude of the determined transverse dynamics disturbance
variable is higher than a disturbance variable threshold value, and
when at least two of the following criteria are fulfilled
longitudinal speed of the vehicle is higher than a longitudinal
speed threshold value of the vehicle; a sensor detected actual yaw
rate is lower than a calculated current yaw rate; and a slip
difference variable describing the slip difference between two
vehicle wheels is lower than a slip differential threshold value.
Description
BACKGROUND AND SUMMARY OF THE INVENTION
This application is a national stage of PCT International
Application No. PCT/EP20081004458, filed Jun. 4, 2008, which claims
priority under 35 U.S.C .sctn.119 to German Patent Application No.
10 2007 029 605.5, filed Jun. 27, 2007, the entire disclosure of
which is herein expressly incorporated by reference.
The invention relates to a device for influencing the transverse
dynamics of a vehicle, especially a motor vehicle, wherein a
transverse dynamics disturbance variable acting on the vehicle (and
especially the chassis) is determined by means of a disturbance
variable determination device, and a chassis intervention braking
intervention is brought about.
The present invention further relates to a transverse dynamics
influencing device for a vehicle, especially a motor vehicle, with
a disturbance variable determination device for determining a
transverse dynamics disturbance variable acting on the vehicle and
especially the chassis.
To increase driving safety when driving a vehicle, such as a motor
vehicle, it is desirable to assist the driver with regard to
suddenly occurring influences or disturbances of the vehicle
transverse dynamics. Such disturbances of the vehicle transverse
dynamics can especially occur with a strong lateral wind in
connection with lateral wind blasts.
In a device for influencing the transverse dynamics of a motor
vehicle in the form of a parallel drive regulation system disclosed
in German patent document DE 40 14 365 A1, the distance to a guide
device is measured during a parallel drive, and with distance
changes (for example, due to a lateral wind), the driving direction
is corrected by braking. However, the described device can only be
used when the mentioned guide device is present.
In a method and a apparatus for influencing the transverse dynamics
of a vehicle disclosed in International Patent. Document WO
2006/037678 A1, a determined disturbance of the transverse dynamics
is dealt with by a change of the wheel load of at least one vehicle
wheel.
One object of the invention, starting from a method and a device of
the above-mentioned type, is to provide a method and apparatus that
increases driving safety in different driving situations.
This and other objects and advantages are achieved by the driving
assistance method and apparatus according to the invention, in
which, the driver needs not react with a (possibly uncontrolled)
steering movement response to a sudden disturbance of the vehicle
transverse dynamics; rather, an automatic compensation or
correction of the disturbance is provided, so that, the driving
safety is increased. This advantageous result is achieved according
to the invention without depending on external devices, such as the
above-mentioned guide device. Also, a chassis intervention as
defined below) is triggered only if the intervention condition is
fulfilled. In this manner, driving situations are excluded in which
a chassis intervention (especially a braking intervention) would
not increase driving safety. Moreover, chassis interventions which
could reduce the driving safety are not carried out.
The intervention condition is fulfilled, if one of the given
criteria or a group of several of the given criteria is fulfilled:
the amount of the determined transverse disturbance variable is
larger than a disturbance variable threshold value, whereby braking
interventions with low transverse dynamics disturbances are
avoided: the longitudinal speed of the vehicle is higher than a
longitudinal speed threshold value, whereby braking interventions
in an uncritical situation with a lower longitudinal vehicle speed
can be avoided: the sensorially detected actual yaw rate is lower
than or equal to a current yaw rate calculated by means of for
example the actual transverse acceleration, to avoid unnecessary
braking interventions in situations where the occurring yaw rate or
transverse acceleration was not mainly caused by the transverse
dynamics disturbance variable; a braking torque variable describing
a braking torque and caused by braking by the driver is lower than
or equal to a braking torque threshold value, so that with braking
processes with large braking torques (such as, for example,
emergency or full braking processes), automatic one-sided braking
interventions can be avoided; a spring path variable describing the
current spring path of a chassis spring of a vehicle wheel is lower
than or equal to a spring path threshold value; a differential
spring path variable describing the difference between the current
spring paths of the two chassis springs of a vehicle axle is lower
than or equal to a differential spring path threshold value; and/or
a slip difference variable describing the slip difference between
two vehicle wheels is lower than or equal to a slip differential
threshold value.
The intervention condition is advantageously fulfilled only if the
amount of the steering wheel angle is lower than or equal to a
steering angle threshold value and/or if the amount of the steering
angle speed is lower than or equal to a steering angle speed
threshold value. In this manner, a chassis intervention with
dynamic steering wheel rotations by the driver can be avoided, so
as not to endanger the driving safety.
Furthermore, the intervention condition can be fulfilled only if
the amount of the stationary transverse acceleration is lower than
or equal to a transverse acceleration threshold value, Chassis
interventions during the driving of dynamic maneuvers (for example,
when driving through turns with correspondingly small turning
radii) are avoided in this manner. A longitudinal speed-dependent
steering wheel limit is thus achieved.
It is also possible to recognize a lateral wind acting on the
chassis of the vehicle and to compensate at least partially a
corresponding disturbance of the transverse dynamics by the chassis
intervention to increase the driving safety in the case of an
occurring lateral wind.
The chassis intervention can be any one or more of the following: a
braking intervention at one or several wheels; an influence of the
wheel loads at one or several wheels; an influence of the servo
torque of a servo motor of a servo steering system; and a change of
one or several wheel drive torques at one or several wheels.
Furthermore, an "interference determination value" can be
determined, which describes the amount of the transverse dynamics
disturbance variable or the amount of the yaw torque, determined by
means of the transverse dynamics disturbance variable, to be
adjusted in order to compensate for the transverse disturbance,
with a variable correlating the two variables. Thereby, with
magnitudes of the intervention determination value below a lower
threshold value, only one of the wheels (especially one of the
non-steerable wheels) can be braked via an associated braking
device. With amounts of the intervention determination value larger
than or equal to the lower threshold value, and lower than an upper
threshold value, only one of the steerable wheels can be braked at
the front axle, via the associated braking device. Furthermore,
with amounts of the intervention determination value larger than or
equal to the upper threshold value, both wheels of the same vehicle
side can be braked via the respective associated braking devices.
In this manner, brake intervention can be adapted to the intensity
of the transverse dynamics disturbance caused by the transverse
dynamics disturbance variable.
Further, there is also the possibility of braking both wheels of
the same vehicle side via the respective associated braking
devices, with the braking force distribution between the steerable
wheel and the corresponding non-steerable wheel being
parameter-dependent. In particular, it can be given in a
vehicle-dependent manner and/or adjusted in a driving
situation-dependent manner.
Other objects, advantages and novel features of the present
invention will become apparent from the following detailed
description of the invention when considered in conjunction with
the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic depiction of a motor vehicle with a design of
the device according to the invention;
FIG. 2 is a block diagram that depicts a progress of an embodiment
of the method according to the invention;
FIG. 3 is a block diagram that illustrates checking of several
criteria of an intervention condition in the validity block VAL of
FIG. 2; and
FIG. 4 is a block diagram that illustrates checking of further
criteria of an intervention condition in switch-off bock OFF of
FIG. 2.
FIG. 1 is a schematic depiction of a motor vehicle with an
embodiment of the device according to the invention. The motor
vehicle 1 has four wheels 2.1-2.4, each being an associated braking
unit 3.1-3.4 operatively connected to it. Each of the braking units
3.1-3.4 is formed for braking of the wheel 2.1-2.4 respectively
associated therewith, and can be activated individually,
independent of the respective other braking units. Thereby,
different braking forces or braking actions can be achieved at the
single wheels 2.1-2.4. (A corresponding activation of the braking
unit with 2.1-2.4 is also called "braking intervention".)
For activating the braking units 3.1-3.4, a braking force
activation unit 4 is provided according to the invention, which is
coupled in signal communication with the braking units 3.1-3.4 The
braking force activation unit 4 itself is coupled in signal
communication with a control unit 5, which has a disturbance
variable determination device 5.1 (also referred to herein as a
"disturbance variable viewer"), and a checking device 5.2. The
control unit 5 is connected to a number of sensors 6.1-6.n.
The sensors 6.1-6.n serve to determine drive-dynamic actual
variables of the vehicle 1, such as an actual yaw rate, a
longitudinal vehicle speed, a steering wheel angle, a steering
angle or an actual transverse acceleration. Corresponding sensor
signals in SS1-SSn are transferred by the sensors 6.1-6.n to the
control unit 5 and thus to the disturbance variable determination
device 5.1 and the checking device.
The disturbance variable determination device 5.1 determines a
transverse dynamics disturbance variable of the vehicle from the
actual variables of the vehicle 1, as is explained in detail in the
German patent application 10 2004 017 638. In this manner, the
disturbance variable determination device 5.1 can be used
especially for determining the disturbance effect of lateral wind
SW acting on the vehicle 1 or its chassis and the influence of the
vehicle transverse dynamics caused thereby. The German patent
application 10 2004 017 638 is insofar referred to explicitly.
The disturbance variable determination device 5.1 generates a
disturbance variable signal SGS, which is transmitted to the
checking device 5.2. The checking device 5.2, determines by means
of a given intervention condition, if a braking intervention shall
be brought about that counteracts the transverse dynamics
disturbance. A corresponding intervention signal BES is transferred
to the braking force activation device 4, which activates at least
one of the braking units 3.1-3.4 by means of corresponding braking
force activation signals BKAS1-BKAS4, in dependence on the
intervention signal BES. The braking force activation signals are
also transmitted to the control unit 5 and especially the
disturbance variable determination device 5.1, to be able to
consider the braking torque caused at one vehicle side and the
influence of the yaw movement of the vehicle resulting therefrom,
during the determination of the transverse dynamic disturbance
variable.
The braking intervention is basically carried out at a wheel 2.1,
2.4 or 2.2, 2.3 of a vehicle side to generate a yaw torque
counter-directed to the transverse disturbance. So as to make the
braking intervention as comfortable as possible for the driver,
only the corresponding non-steerable wheel 2.1 or 2.2 can be braked
exclusively, or at least in a first braking intervention stage at
the rear axle of the vehicle, such that possible noticeable
feedbacks at the steering wheel of the vehicle 1 remain as low as
possible. How strong possible feedbacks on the steering wheel are
during the wheel-individual braking of a steerable wheel 2.3 or 2.4
depends on the vehicle type and its chassis design. Whether the
braking intervention takes place at a steerable wheel 2.3 or 2.4
and/or at a non-steerable wheel 2.1 or 2.2, is adapted individually
to the vehicle type. With vehicle types where, during braking of a
steerable wheel 2.3 or 2.4, only small feedbacks occur at the
steering wheel, the steerable wheel 2.3 or 2.4 of the same vehicle
side can be braked alternatively or in addition to the
non-steerable rear wheel 2.1 or 2.2, to compensate for transverse
disturbances.
It is thus possible to design the braking intervention in such a
manner that the wheels 2.1, 2.4 or 2.2, 2.3 of one vehicle side are
braked simultaneously. The braking force distribution between the
steerable front wheel 2.3 or 2.4 and the rear wheel 2.2 or 2.1 on
this vehicle side can be preset dependent upon the vehicle and/or
adjusted in dependence on the driving situation. The braking force
distribution between the steerable front wheel 2.3 or 2.4 and the
non-steerable rear wheel 2.2 or 2.1 can for example be considered
by parameters such as the amount of the transverse dynamics
disturbance variable, the steering angle, the brake torque caused
on the vehicle side and the influence of the yaw movement of the
vehicle resulting therefrom during the determination of the
transverse dynamic disturbance variable.
An intervention determination value, which describes the amount of
the transverse dynamics disturbance variable or the amount of the
yaw torque to be adjusted, can be determined in the checking device
5.2 using the transverse dynamics disturbance variable for
compensating the transverse disturbance, or the amount of another
variable correlating with one of the two variables. A multi-stage
braking intervention can then take place as a function of the
intervention determination value, wherein the following
possibilities result: a) The intervention determination value
exceeds the intervention threshold value and is smaller than a
preset lower threshold value: First, only one wheel 2.1 or 2.2 or
2.3 or 2.4 is braked (preferably, a non-steerable wheel 2.3 or
2.4). Only if this braking intervention carried out exclusively at
one of the wheels 2.1 or 2.2 or 2.3 or 2.4 does not show a
sufficient effect, the further wheel 2.1 or 2.2 or 2.3 or 2.4 of
the same vehicle side is braked. b) If the intervention
determination value is higher than or equal to the lower threshold
value, both wheels 2.1, 2.4 or 2.2, 2.3 of the same vehicle side
are braked to reduce the transverse dynamics influence of the
vehicle 1 by the transverse dynamics and to ensure a high driving
safety. c) In a further development, it is also possible to provide
three intervention stages: With an intervention determination value
higher than the intervention threshold value and lower than the
lower threshold value, only one of the non-steerable wheels 2.1 or
2.2 is braked via the respective associated braking devices 3.1 or
3.2. With an intervention determination value higher than or equal
to the lower threshold value and smaller than an upper threshold
value, only one of the steerable wheels 2.3 or 2.4 is braked at the
front axle via the respective associated braking device 3.3 or 3.4.
With an intervention determination value higher than or equal to
the upper threshold value, both wheels 2.1, 2.4 or 2.2, 2.3 of the
same vehicle side are braked by the respective associated braking
devices 3.1, 3.4 or 3.2, 3.3.
If a lateral wind blast SW (FIG. 1) acts, for example, on the
chassis of the vehicle 1 seen from the right in the drive
direction, the right rear wheel 2.2 and/or the right front wheel
2.3 can be braked, so as to generate a yaw torque on the vehicle 1
around its vertical axis in the clockwise direction. With a lateral
wind acting on the vehicle 1 from the left, the directions are
exactly reversed, wherein the left front wheel 2.4 and or the left
rear wheel 2.1 are then braked.
The disturbance of the transverse dynamics by the lateral wind SW
is at least compensated partially by the braking intervention. The
disturbance determination device 5 and/or the braking force
activation device 4 is/are formed for this purpose to determine a
necessary braking force at a wheel or several wheels 2.1-2.4 of the
vehicle 1, so as to compensate the occurred disturbance of the
vehicle transverse dynamics correspondingly as already
mentioned.
The driver of the vehicle 1 is thus assisted during the
compensation of a disturbance of the vehicle transverse dynamics,
such as for example a lateral wind blast. The disturbance of the
transverse dynamics is thus reduced automatically or completely
compensated, helping to increase driving safety.
In the following, an embodiment of the method according to the
invention is explained with references to FIG. 2. FIG. 2 is a block
diagram of an embodiment of the method according to the invention
for influencing the transverse dynamics of a vehicle, especially
the motor vehicle 1 according to FIG. 1.
The method according to the invention starts with the determination
of the transverse dynamics disturbance variable FSW in a viewer
block OBS, based on the of the drive-dynamic actual values of the
vehicle measured by means of the sensors 6.1 to 6.n, and on the
braking force activation signals BKAS1-BKAS4. The method for
determining the transverse dynamics disturbance variable used in
the viewer block OBS is described in German patent application DE
10 2004 017 638 A1, which is referred to in this connection.
The transverse dynamics disturbance variable FSW, determined in
this manner by means of the viewer block OBS, is subsequently high
pass filtered in a high pass filter HP to filter out stationary
parts of the transverse dynamics disturbance variable, which are
not considered in the following method. (Only dynamic parts of the
transverse dynamics disturbance variable FSW are considered in the
further method.) The highpass filter HP generates the high pass
filtered transverse dynamics disturbance variable, which
corresponds to the disturbance variable signal SGS in the present
case, and is transferred to the checking device 5.2 of the control
unit.
In the checking device 5.2 it is checked if a preset intervention
condition is fulfilled. The intervention condition has several
criteria with the embodiment of the method, which for example
respectively have to be fulfilled individually to fulfill the
intervention condition. These criteria serve to exclude drive
situations, in which no automatic braking intervention is to be
caused.
It is checked in a hysteresis block as a first criterion, whether
the disturbance variable signal SGS (that is, the high pass
filtered transverse dynamics disturbance variable) is larger than a
preset activation threshold value, or is smaller than a
deactivation threshold value. The activation threshold value is
larger than the deactivation threshold value, so that a hysteresis
is formed. If the disturbance variable signal is larger than the
activation threshold value, a first flag F1=1 is set. If, however,
the disturbance variable signal SGS is smaller than the
deactivation threshold value, the first flag K1=0 is set:
SGS>activation threshold value F1=1 or SGS<deactivation
threshold value F1=0.
Further criteria are checked in a validity block VAL, for example
eight criteria K2 to K9, via which the current drive situation is
judged, as is depicted in detail in FIG. 3 schematically. The
following criteria are checked to determine whether: second
Criterion K2: the amount of the steering wheel angle .delta. is
smaller than or equal to the steering wheel threshold value
.delta..sub.s; third Criterion K3: the amount of the steering wheel
angle speed {dot over (.delta.)} is smaller than or equal to a
steering wheel speed threshold value {dot over (.delta.)}.sub.s;
fourth Criterion K4: the longitudinal vehicle speed v.sub.x is
higher than a longitudinal vehicle speed threshold value v.sub.xs;
fifth Criterion K5: the sensorially detected actual yaw rate {dot
over (.PSI.)} is lower than or equal to a calculated current yaw
rate {dot over (.PSI.)}.sub.mod (calculated on the basis of a given
vehicle model), which describes the connection between the
transverse acceleration and yaw rate, by means of the measures
actual transverse acceleration a.sub.y; sixth Criterion K6: the
amount of the stationary transverse acceleration a.sub.y,stat is
smaller than or equal to a transverse acceleration threshold value
a.sub.y,stat,s; seventh Criterion K7: braking torque M.sub.br
caused by the driver by braking, which depicts a braking torque
variable with the embodiment is lower or equal to a braking torque
threshold value M.sub.brs; eighth Criterion K8: the current spring
paths z.sub.VL, z.sub.VR, z.sub.HL, z.sub.HR at the chassis springs
of the vehicle wheels 2.1 (HL), 2.2 (HR), 2.3 (VR), 2.4 (VL), which
for example depicts a spring path variable, are lower or equal to a
spring path threshold value z.sub.s; it is checked additionally if
the amount of a difference spring path variable, which is for
example formed by the difference |zHP.sub.VL-zHP.sub.VR| of the
current spring paths zHP.sub.VL, zHP.sub.VR especially high
pass-filtered via a high pass is formed at the two chassis springs
of a vehicle axle, is smaller or equal to a difference spring path
threshold value .DELTA.z.sub.s ninth Criterion K9: a slip
differential value, which is here formed by the slip difference
between two vehicle wheels is lower or equal to a slip difference
threshold value; a first slip difference
|.lamda..sub.VL-.lamda..sub.VR| is for example compared between the
two front wheels 2.3 (VR), 2.4 (VL) and a second slip difference
|.lamda..sub.HL-.lamda..sub.HR| between the two rear wheels 2.1
(HL), 2.2 (HR) with a front axle slip difference threshold value
.lamda.v.sub.s or a rear axle slip difference threshold value
.lamda.v.sub.s:
|.lamda..sub.HL-.lamda..sub.HR|.ltoreq..lamda..sub.Hs
|.lamda..sub.VL-.lamda..sub.VR|.ltoreq..lamda..sub.Vs
It is determined via the logic block AND, if all of the eight
criteria K2 to K9 are fulfilled (that is, whether all inequalities
given in FIG. 3 are fulfilled and thus "true"). If so, the second
flag is set F2=1. On the other hand, if one or more the criteria K2
to K9 checked in the validity block are not fulfilled, the second
flag F2=0.
In a switch-off block OFF (FIG. 2, and shown in more detail in FIG.
4), one or more switch-off criteria K10, K11, K12 are considered. A
third flag F3 is set to F3=1, if at least one of the switch-off
criteria is fulfilled. The switch-off criteria checked with the
embodiment described here are: first Switch-Off Criterion K10: the
amount of the steering wheel angle .delta. is larger than the
steering wheel threshold value .delta..sub.s; second Switch-Off
Criterion K11: the amount of the steering angle speed {dot over
(.delta.)} is higher than the steering angle speed threshold value
{dot over (.delta.)}.sub.s; third Switch-Off Criterion K12: the
braking torque M.sub.br caused by the driver by braking is higher
than the brake torque threshold value M.sub.brs.
If none of the switch-off criteria K10, K11, K12 is fulfilled, the
third flag F3 is set to F3=0. The switch-off criteria K10, K11, K12
are interconnected to the third flag F3 in the or interconnection
block OR.
Considering the three flags F1, F2, F3 and a fourth flag F4, the
intervention signal BES is determined in a logic block LOG, which
is fed back to an input of the logic block LOG as the fourth flag
F4. In the logic block, the values of the flags F1, F2, F3, F4,
present in the current method cycle, and also partially the values
of the flags F1, F2, F3, F4 from the previous method cycle n-1 are
used for determining the intervention signal BES. In the present
case, the values of the first flag F1, the second flag F2, and the
fourth flag F4 from the previous method are considered.
The following is valid as necessary conditions for an intervention
signal BES triggering a braking process: The third flag F3=0 (that
is, none of the switch-off criteria K10, K11, K12 is fulfilled);
and the first flag F1=1, that is, the conditions defined in the
hysteresis block HYS have to be fulfilled.
In the current method cycle n, the intervention signal BES is
BES(n)=F4(n)=1. if one of the combinations occurring in the
following table occurs. Each row of the table corresponds to a
combination of conditions which triggers or maintains a braking
operation in the prevailing method cycle:
TABLE-US-00001 F2(n - 1) F2(n) F1(n - 1) F1(n) F3(n) F4(n - 1) 0 0
1 1 0 1 0 1 0 1 0 0 0 1 0 1 0 1 0 1 1 1 0 1 1 0 1 1 0 1 1 1 0 1 0 0
1 1 0 1 0 1 1 1 1 1 0 1
A braking process at one or more wheels is triggered or maintained
via the braking force activation device 4, if the intervention
signal is BES=1.
A new method cycle starts subsequently analogous to the
above-described method cycle. At the start of the first method
cycle, respective starting values F1(start), F2(start), F3(start)
and F4(start) are given as values of the flags F1, F2, F3, F4 for
the previous method cycle, so that the method can also work with
the first method cycle (e.g., when starting the vehicle). Such an
approach is known with cyclic methods. The start values can for
example be given as follows: F1(Start)=0, F2(Start)=0, F3(Start)=0
and F4(Start)=0.
The embodiment described here carries out a braking intervention as
chassis intervention to counteract the transverse dynamics
disturbance.
Alternatively or in addition, the transverse dynamics disturbance
can also be compensated, at least partially, by other chassis
interventions: The servo torque of a servomotor (especially, an
electrical servo motor) for the vehicle steering system can be
influenced, so that the driver is supported when countersteering.
The servo-torque is directed in such a manner that the driver is
prompted to steer against the transverse dynamics disturbance. If
the driver does not hold the steering wheel, and if he complies
with the servo torque of the servo motor, a so-to-speak automatic
countersteering takes place. The wheel load of one or more wheels
2.1-2.4 of the vehicle 1 can be changed, for example by the
actuation of an active spring or damper system associated with the
respective wheel 2.1, 2.2, 2.3, 2.4, or an active stabilisator of
the vehicle. The wheel load of two wheels opposite each other 2.1
(HL) and 2.3 (VR) or 2.2 (HR) and 2.4 (VL)b can be increased with
regard to the two other wheels 2.2 (HR) and 2.4 (VL) or 2.1 (HL)
and 2.3 (VR). A transverse force is generated by the axle geometry,
especially the toe-in. Alternatively or in additional, the wheel
loads can also be reduced at two wheels diagonally opposite. This
transverse force can be used to compensate at least partially for
the transverse dynamics disturbance. Analogous to carrying out a
braking process, there is also the possibility to distribute the
wheel drive force unequally on the two vehicle sides, which can for
example be achieved by an actuatable axle differential. The wheel
drive force can thus be increased at one vehicle side and/or be
reduced at the other. A yaw movement is effected due to the to the
unequal wheel drive forces on both vehicle sides. This yaw movement
takes place against the transverse dynamics disturbance and can
thus at least reduce this and compensate it completely in the ideal
case.
The foregoing disclosure has been set forth merely to illustrate
the invention and is not intended to be limiting. Since
modifications of the disclosed embodiments incorporating the spirit
and substance of the invention may occur to persons skilled in the
art, the invention should be construed to include everything within
the scope of the appended claims and equivalents thereof.
* * * * *